This invention relates to improvements in fuel injection systems for internal combustion engines and including an improved injection pump for such systems and other purposes and an improved fuel injector.
It is generally recognized that the fuel injection system as used on high compression diesel engines, for example, is more efficient than the carburetor system traditionally used on the relatively low compression gasoline engine and with the current emphasis on fuel conservation and regulation of polutants from exhaust gases of internal combustion engines, interest in the fuel injection system for gasoline engines is rising in popularity with the result that various fuel injections systems for such engines have been designed to meet current standards for mileage and emmission controls. However, due to the various different operating characteristics between gasoline and diesel engines, the respective fuel injections systems for such engines as presently designed are sufficiently different to accomplish their respective purposes that they are not interchangeable and one type of engine cannot be converted to the other without structural changes in the engine as is well known. Thus, the present necessity for different injection systems for gasoline and diesel engines is a duplication in effort and expense.
An important consideration in the design of fuel injection systems is the fact that diesel fuel for the diesel engine has good lubricating properties while fuel such as gasoline, gasahol, alcohol and the like for gasoline engines has relatively poor lubricating properties. Consequently, while the injection pump and injector in a diesel injection system will receive adequate lubrication from the fuel pumped, this does not occur with gasoline engine fuels and, accordingly, present type fuel injection systems for gasoline engines include special design features to provide some form of auxiliary or supplemental fluid source of lubrication for the pump and injector for without lubrication, either from the fuel pumped or supplemental fluid source, present injection systems will gall and become inoperable.
With this observation in mind, it is one of the important objects of this invention to provide an improved fuel injection system for internal combustion engines that include an improved direct injection pump and injector designed to operate efficiently with any type of fuel irrespective of its lubricating properties and without association with such fluids or with supplementary sources of selected fluids for purposes of lubrication.
A further object herein is to provide a fuel injection system of the above class that is capable of efficiently operating either a gasoline or diesel engine on any combustible fuel or any combination of such fuels.
In the typical fuel injection system for multiple cylinder engines, the pumps are mounted in a common housing for operation by separate cams on a camshaft operated from the engine at half engine speed for four cycle engines and at engine speed for two cycle engines. The pump assembly includes separate rotatable grooved plungers operating at a constant full stroke between separate fuel inlet and outlet ports in a timed sequence to synchronize the measured amount of fuel delivered to each cylinder. Such timing depends upon rotation of the plungers effected by a unitary control means such as the commonly used control rack connected to all pumps in a well known manner. Thus, by reason of such unitary control, if one pump becomes locked in inoperative position for any reason such as by galling, the control rack is also rendered inoperable and the remaining pumps become immovable at various positions relative to fuel intake and fuel outlet so as to disrupt the designed timed cycles of the system and resulting in the engine stopping or running out of control. Also typical in such injection systems is the wobble plate means for operating the pumps instead of the camshaft and control rack. With the wobble plate system, fuel is metered by a single axially located rotary valve in the wobble plate unit and when one of the pumps becomes inoperative, speed control of the engine is no longer possible. Accordingly, it is another important object herein to provide an improved fuel injection pump and injector for use in a multiple cylinder internal combustion engine which includes a control system separately operable relative to each pump so that if one pump fails, fuel injection from such pump is stopped and the remaining pumps will continue to operate in their intended cycle.
Another feature of this invention is to provide an improved fuel injection system as characterized that will permit an ordinary gasoline engine to be converted from the carburetor system to the injection system by removal of the carburetor system components such as spark plugs, ignition, coil, carburetor, points, fuel pump and the like but with no other structural changes in the engine. For this purpose, another object herein is to associate a pump of the above class with a novel combined fuel injector and thermal heater or glow plug arranged in a single housing for mounting in the standard spark plug port to eliminate the requirement of boring a separate port in the engine to the combustion chamber for use of such heater when desired.
Still other objects of this invention are to provide a fuel injection system as characterized which can be adjusted for operation on high and low compression engines and precisely meter and efficiently atomize only that amount of fuel required for engine operation at any given speed and which materially increases the efficiency of the internal combustion engine to produce a substantially higher number of miles per gallon of fuel than present fuel systems.
A further object is to provide a fuel injection system of the above class that produces efficient, complete and clean burning of the fuel whereby pollutants in exhaust gases are only minimal and far below current standards and regulations on emmision control.
Another object to to provide a fuel injection system as characterized that will operate efficiently on either two or four cycle single or multiple cylinder engines without structural changes in such engines.
Yet another object herein is to provide an improved injection pump as characterized wherein because the working parts are sealed within a suitable housing and require no lubrication from the fluid pumped or from extraneous materials affecting such fluids, such pump has special utility in use with chemical fluids that must be kept free of contamination.